user: Question: Which opponent played on July 15?
Columns: ['Date', 'Opponent', 'Score', 'Loss', 'Attendance', 'Record']
Types: ['text', 'text', 'text', 'text', 'real', 'text']
Sample row: ['July 1', 'Orioles', '7 - 4', 'Hentgen (7-6)', 43377.0, '36-45']
SQL:

assistant: SELECT "Opponent" FROM "Table" WHERE "Date" = 'July 15';