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

### Instruction:
Who was the young rider classification when Alessandro Petacchi won?

### Inputs:
table_name: table, columns: ['Stage', 'Winner', 'General classification', 'Points classification', 'Mountains classification', 'Young rider classification']

### Response:
SELECT Young rider classification FROM table WHERE Winner = Alessandro Petacchi