user: Question: Who is the opponent when the attendance is N/A?
Columns: ['Competition', 'Round', 'Opponent', 'Result', 'Score', 'Home/Away', 'Venue', 'Attendance', 'Date']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Super League XIV', '1', 'Crusaders', 'Win', '28-16', 'Home', 'The Willows', '4,026', '14/02/2009']
SQL:

assistant: SELECT "Opponent" FROM "Table" WHERE "Attendance" = 'N/A';