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

### Instruction:
When in the 1st league position, how many people watch as they faced West Ham United?

### Inputs:
table_name: table, columns: ['Date', 'Opponents', 'Result F–A', 'Attendance', 'League position']

### Response:
SELECT MIN Attendance FROM table WHERE League position = 1st AND Opponents = west ham united