user: Question: Who proceeded to the quarter finals with a points margin of 21?
Columns: ['Proceed to Quarter-final', 'Match points', 'Aggregate score', 'Points margin', 'Eliminated from competition']
Types: ['text', 'text', 'text', 'real', 'text']
Sample row: ['London Wasps', '4 – 0', '72 – 29', 43.0, 'NEC Harlequins']
SQL:

assistant: SELECT "Proceed to Quarter-final" FROM "Table" WHERE "Points margin" = 21.0;