how many politicians are there from the city of view of haarlem from the northwest ?
SELECT DISTINCT COUNT attr_open var_uri attr_close where brack_open dbr_View_of_Haarlem_from_the_Northwest,_with_the_Bleaching_Fields_in_the_Foreground dbp_city var_x sep_dot var_x dbo_leaderName var_uri brack_close