user: Question: Which Round has an Opponent of Ryan Bixler?
Columns: ['Res.', 'Record', 'Opponent', 'Method', 'Event', 'Round']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Win', '19-9', 'Zac Kelley', 'Submission', 'Stacked 3', '1']
SQL:

assistant: SELECT "Round" FROM "Table" WHERE "Opponent" = 'Ryan Bixler';