user: Question: Which track was used on September 12, 1981? 
Columns: ['Rnd', 'Date', 'Race Name', 'Length', 'Track', 'Location', 'Type', 'Pole Position', 'Winning Driver']
Types: ['real', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, 'May 24, 1981', 'Indianapolis 500-Mile Race', 'mi (km)', 'Indianapolis Motor Speedway', 'Speedway , Indiana', 'Paved oval', 'Bobby Unser', 'Bobby Unser']
SQL:

assistant: SELECT "Track" FROM "Table" WHERE "Date" = 'September 12, 1981';