user: Question: How many rounds have an Opponent of sakae kasuya?
Columns: ['Res.', 'Record', 'Opponent', 'Method', 'Event', 'Round', 'Time']
Types: ['text', 'text', 'text', 'text', 'text', 'real', 'text']
Sample row: ['Loss', '10-8-1', 'Issei Tamura', 'Decision(unanimous)', 'Shooto', 2.0, '5:00']
SQL:

assistant: SELECT COUNT("Round") FROM "Table" WHERE "Opponent" = 'sakae kasuya';