Question: What are the names of countries that have both players with position forward and players with position defender?
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"