user: Question: who was the opponent where the date was the 21st?
Columns: ['Date', 'Opponent', 'Venue', 'Result', 'Attendance', 'Competition', 'Man of the Match']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['1st', 'Milton Keynes Lightning', 'Home', 'Won 5-4', '1,336', 'League', 'Terry Miles']
SQL:

assistant: SELECT "Opponent" FROM "Table" WHERE "Date" = '21st';