user: Question: Which Round has the Winning Driver of Brendon Hartley, and a Date of 27 April?
Columns: ['Round', 'Circuit', 'Date', 'Pole Position', 'Fastest Lap', 'Winning Driver', 'Winning Team']
Types: ['real', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, 'Oulton Park', '24 March', 'Jaime Alguersuari', 'John Martin', 'Oliver Turvey', 'Carlin Motorsport']
SQL:

assistant: SELECT "Round" FROM "Table" WHERE "Winning Driver" = 'Brendon Hartley' AND "Date" = '27 April';