user: Question: What is the round number of the match with Michael Buell as the opponent?
Columns: ['Res.', 'Record', 'Opponent', 'Round', 'Time', 'Location']
Types: ['text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['Loss', '26-17-2', 'Hideo Tokoro', 1.0, '0:39', 'Tokyo , Japan']
SQL:

assistant: SELECT "Round" FROM "Table" WHERE "Opponent" = 'Michael Buell';