user: Question: Which Winning Driver has a Circuit of Circuit Zandvoort?
Columns: ['Round', 'Date', 'Event', 'Circuit', 'Winning Driver', 'Winning Team']
Types: ['real', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, 'April 26', 'International Procar Meeting', 'Donington Park', 'Jan Lammers', 'BMW Holland']
SQL:

assistant: SELECT "Winning Driver" FROM "Table" WHERE "Circuit" = 'Circuit Zandvoort';