Among the players whose bowling skill is "Legbreak", when was the oldest one of them born?
the oldest refers to min(DOB); date of birth refers to DOB
SELECT MIN(T1.DOB) FROM Player AS T1 INNER JOIN Bowling_Style AS T2 ON T1.Bowling_skill = T2.Bowling_Id WHERE T2.Bowling_Skill = 'Legbreak'
database name:db_id soccer_2016
Batting_Style table Batting_Style Cols: batting id dtype integer, batting hand dtype text, 
Bowling_Style table Bowling_Style Cols: bowling id dtype integer, bowling skill dtype text, 
City table City Cols: city id dtype integer, city name dtype text, country id dtype integer, 
Country table Country Cols: country id dtype integer, country name dtype text, 
Extra_Type table Extra_Type Cols: extra id dtype integer, extra name dtype text, 
Extra_Runs table Extra_Runs Cols: match id dtype integer, over id dtype integer, ball id dtype integer, extra type id dtype integer, extra runs dtype integer, innings number dtype integer, 
Out_Type table Out_Type Cols: out id dtype integer, out name dtype text, 
Outcome table Outcome Cols: outcome id dtype integer, outcome type dtype text, 
Player table Player Cols: player id dtype integer, player name dtype text, date of birth dtype date, batting hand dtype integer, bowling skill dtype integer, country name dtype integer, 
Rolee table Rolee Cols: role id dtype integer, role description dtype text, 
Season table Season Cols: season id dtype integer, man of the series dtype integer, orange cap dtype integer, purple cap dtype integer, season year dtype integer, 
Team table Team Cols: team id dtype integer, team name dtype text, 
Toss_Decision table Toss_Decision Cols: toss id dtype integer, toss name dtype text, 
Umpire table Umpire Cols: umpire id dtype integer, umpire name dtype text, umpire country dtype integer, 
Venue table Venue Cols: venue id dtype integer, venue name dtype text, city id dtype integer, 
Win_By table Win_By Cols: winning id dtype integer, winning type dtype text, 
Match table Match Cols: Match_Id dtype integer, team 1 dtype integer, team 2 dtype integer, match date dtype date, season id dtype integer, venue id dtype integer, toss winner dtype integer, toss decide dtype integer, winning type dtype integer, winning margin dtype integer, outcome type dtype integer, match winner dtype integer, man of the match dtype integer, 
Ball_by_Ball table Ball_by_Ball Cols: match id dtype integer, over id dtype integer, ball id dtype integer, innings number dtype integer, team batting dtype integer, team bowling dtype integer, striker batting position dtype integer, Striker dtype integer, non striker dtype integer, Bowler dtype integer, 
Batsman_Scored table Batsman_Scored Cols: match id dtype integer, over id dtype integer, ball id dtype integer, runs scored dtype integer, innings number dtype integer, 
Player_Match table Player_Match Cols: match id dtype integer, player id dtype integer, role id dtype integer, team id dtype integer, 
Wicket_Taken table Wicket_Taken Cols: match id dtype integer, over id dtype integer, ball id dtype integer, player out dtype integer, kind out dtype integer, Fielders dtype integer, innings number dtype integer, 
