user: Question: How many rounds did the match go for the Bellator 72 event?
Columns: ['Res.', 'Record', 'Opponent', 'Method', 'Event', 'Round', 'Time', 'Location']
Types: ['text', 'text', 'text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['Loss', '16–6–2', 'Douglas Lima', 'KO (head kick)', 'Bellator 100', 2.0, '4:33', 'Phoenix, Arizona , United States']
SQL:

assistant: SELECT "Round" FROM "Table" WHERE "Event" = 'Bellator 72';