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

### Instruction:
What date did the episode with 8.61 million U.S. viewers originally air?

### Inputs:
table_name: table, columns: ['№', 'Title', 'Directed by', 'Written by', 'Original air date', 'Production code', 'U.S. viewers (million)']

### Response:
SELECT Original air date FROM table WHERE U.S. viewers (million) = 8.61