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

### Instruction:
What number episode had a 4.2 rating?

### Inputs:
table_name: table, columns: ['No.', 'Episode', 'Rating', 'Share', 'Rating/share (18-49)', 'Viewers (millions)', 'Rank (timeslot)', 'Rank (night)']

### Response:
SELECT MIN No. FROM table WHERE Rating = 4.2