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

### Instruction:
Who was the visiting team on weeks under 12 and at Sports Authority Field at Mile High?

### Inputs:
table_name: table, columns: ['Week', 'Date', 'Visiting Team', 'Final Score', 'Host Team', 'Stadium']

### Response:
SELECT Visiting Team FROM table WHERE Week < 12 AND Stadium = sports authority field at mile high