user: Question: Who was the opponent on May 20?
Columns: ['Date', 'Opponent', 'Score', 'Loss', 'Attendance', 'Record']
Types: ['text', 'text', 'text', 'text', 'real', 'text']
Sample row: ['May 1', 'New York Mets', '3-6', 'Ayala (1-1)', 27333.0, '13-12']
SQL:

assistant: SELECT "Opponent" FROM "Table" WHERE "Date" = 'May 20';