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

### Instruction:
Which episode number aired on 18 october 2012?

### Inputs:
table_name: table, columns: ['Episode no.', 'Airdate', 'Dave Viewers', 'Dave Rank', 'Rank (cable)', 'Dave ja vu Viewers', 'Total viewers']

### Response:
SELECT MIN Episode no. FROM table WHERE Airdate = 18 October 2012