user: Question: What is the date of the race when Jack Brabham is in the pole position and the circuit is Spa-Francorchamps?
Columns: ['Race', 'Circuit', 'Date', 'Pole position', 'Fastest lap', 'Winning driver', 'Constructor', 'Tyre', 'Report']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Argentine Grand Prix', 'Buenos Aires', '7 February', 'Stirling Moss', 'Stirling Moss', 'Bruce McLaren', 'Cooper - Climax', 'D', 'Report']
SQL:

assistant: SELECT "Date" FROM "Table" WHERE "Pole position" = 'Jack Brabham' AND "Circuit" = 'Spa-Francorchamps';