user: Question: What is every pole position for the Castle Combe circuit and Robbie Kerr is the winning driver?
Columns: ['Round', 'Circuit', 'Date', 'Pole Position', 'Fastest Lap', 'Winning driver', 'Winning team']
Types: ['real', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, 'Brands Hatch', '1 April', 'James Courtney', 'James Courtney', 'Robbie Kerr', 'Alan Docking Racing']
SQL:

assistant: SELECT "Pole Position" FROM "Table" WHERE "Circuit" = 'Castle Combe' AND "Winning driver" = 'Robbie Kerr';