user: Question: What country did Gil play against on 21–23 September 2007?
Columns: ['Edition', 'Round', 'Date', 'Partnering', 'Against', 'Surface', 'Opponents', 'W–L', 'Result']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['2004 Davis Cup Europe/Africa Group II', '1R', '9–11 April 2004', 'Leonardo Tavares', 'Tunisia', 'Hard', 'Haithem Abid Malek Jaziri', 'Win', '7–5, 6–3, 6–2']
SQL:

assistant: SELECT "Against" FROM "Table" WHERE "Date" = '21–23 September 2007';