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

### Instruction:
During which stage was the Intergiro classification held by Miguel Indurain, the Points classification held by Mario Cipollini, and the Young rider classification held by Leonardo Sierra?

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

### Response:
SELECT Stage FROM table WHERE Intergiro classification = miguel indurain AND Points classification = mario cipollini AND Young rider classification = leonardo sierra