CREATE TABLE table_name_21 (away_captain VARCHAR, venue VARCHAR, home_captain VARCHAR)

Who was the Away Captain when the Home Captain was Joe Darling at Melbourne Cricket Ground?
SELECT away_captain FROM table_name_21 WHERE venue = "melbourne cricket ground" AND home_captain = "joe darling"
SELECT "away_captain" FROM "table_name_21" WHERE "home_captain" = "joe darling" AND "melbourne cricket ground" = "venue"