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

### Instruction:
What is the lowest series episode with a production code of 406?

### Inputs:
table_name: table, columns: ['Series episode', 'Season episode', 'Title', 'U.S. viewers (millions)', 'Original U.S. airdate', 'Prod. code']

### Response:
SELECT MIN Series episode FROM table WHERE Prod. code = 406