Question: Return the names of countries that have players that play the Forward position, as well as players who play the Defender position.
SQL: 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"