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

### Instruction:
Which championship has Roger Federer as an opponent on a clay surface in a year earlier than 2007?

### Inputs:
table_name: table, columns: ['Outcome', 'Year', 'Championship', 'Surface', 'Opponent', 'Score']

### Response:
SELECT Championship FROM table WHERE Opponent = roger federer AND Surface = clay AND Year < 2007