user: Question: What was tyre that was made by Cooper - Bristol that was driven by Bob Gerard?
Columns: ['Entrant', 'Constructor', 'Chassis', 'Tyre', 'Driver', 'Rounds']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Officine Alfieri Maserati', 'Maserati', '250F A6GCM', 'P', 'Juan Manuel Fangio', '1, 3']
SQL:

assistant: SELECT "Tyre" FROM "Table" WHERE "Constructor" = 'Cooper - Bristol' AND "Driver" = 'Bob Gerard';