user: Question: What opposing teams playing on 11/04/1999?
Columns: ['Opposing Teams', 'Against', 'Date', 'Venue', 'Status']
Types: ['text', 'real', 'text', 'text', 'text']
Sample row: ['Scotland', 21.0, '20/02/1999', 'Twickenham , London', 'Five Nations']
SQL:

assistant: SELECT "Opposing Teams" FROM "Table" WHERE "Date" = '11/04/1999';