user: Question: Who did the Lightning play at the Mellon Arena?
Columns: ['Date', 'Opponent', 'Location', 'Time', 'Result']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['Saturday, September 20', 'Pittsburgh', 'Mellon Arena', '7:30pm', '5-4 W (SO)']
SQL:

assistant: SELECT "Opponent" FROM "Table" WHERE "Location" = 'Mellon Arena';