user: Question: What tournament did Smeets play against Mark Nielsen?
Columns: ['Date', 'Tournament', 'Surface', 'Opponent in the final', 'Score']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['2 May 2005', 'Seogwipo', 'Hard', 'James Auckland', '7–5, 6–3']
SQL:

assistant: SELECT "Tournament" FROM "Table" WHERE "Opponent in the final" = 'Mark Nielsen';