user: Question: In the circuit Showevent Olympiastadion München, where the winning driver is Bruno Spengler, what is the pole position?
Columns: ['Round', 'Circuit', 'Date', 'Pole Position', 'Fastest Lap', 'Winning Driver', 'Winning Team']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['1', 'Hockenheimring', '1 May', 'Bruno Spengler', 'Bruno Spengler', 'Bruno Spengler', 'HWA Team']
SQL:

assistant: SELECT "Pole Position" FROM "Table" WHERE "Winning Driver" = 'Bruno Spengler' AND "Circuit" = 'Showevent Olympiastadion München';