Return the names of countries that have players that play the Forward position, as well as players who play the Defender position.
SELECT T1.Country_name FROM country AS T1 JOIN match_season AS T2 ON T1.Country_id  =  T2.Country WHERE T2.Position  =  "Forward" INTERSECT SELECT T1.Country_name FROM country AS T1 JOIN match_season AS T2 ON T1.Country_id  =  T2.Country WHERE T2.Position  =  "Defender"
countries with players that play Forward = SELECT Country_name FROM country JOIN match_season ON country.Country_id = match_season.Country WHERE Position = 'Forward'; countries with players that play Defender = SELECT Country_name FROM country JOIN match_season ON country.Country_id = match_season.Country WHERE Position = 'Defender';