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

### Instruction:
Which date had a year under 1988, loser of Philadelphia Eagles, location of Giants Stadium, and a result of 21-0?

### Inputs:
table_name: table, columns: ['Year', 'Date', 'Winner', 'Result', 'Loser', 'Location']

### Response:
SELECT Date FROM table WHERE Year < 1988 AND Loser = philadelphia eagles AND Location = giants stadium AND Result = 21-0