Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
In Round 6, how many winning drivers were there?

### Inputs:
table_name: table, columns: ['Rnd', 'Race Name', 'Pole position', 'Fastest lap', 'Winning driver', 'Winning team', 'Report']

### Response:
SELECT COUNT Winning driver FROM table WHERE Rnd = 6