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

### Instruction:
What is the name of the tournament played on Sep 20, 1981, ending with a margin of vicroty of 2 strokes?

### Inputs:
table_name: table, columns: ['Date', 'Tournament', 'Winning score', 'Margin of victory', 'Runner(s)-up']

### Response:
SELECT Tournament FROM table WHERE Margin of victory = 2 strokes AND Date = sep 20, 1981