user: Question: What was the average attendance when the New York Mets were opponents with a record of 51-33?
Columns: ['Date', 'Opponent', 'Score', 'Loss', 'Attendance', 'Record']
Types: ['text', 'text', 'text', 'text', 'real', 'text']
Sample row: ['July 1', '@ Chicago Cubs', '4-3', 'Prior (5-2)', 38973.0, '48-31']
SQL:

assistant: SELECT AVG("Attendance") FROM "Table" WHERE "Opponent" = 'New York Mets' AND "Record" = '51-33';