user: Question: How many total rounds used the Submission (choke) method?
Columns: ['Res.', 'Record', 'Opponent', 'Method', 'Event', 'Round', 'Time', 'Location']
Types: ['text', 'text', 'text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['Win', '29-7-2', 'Thomas Denny', 'KO (punches)', 'IFL 11', 2.0, '0:50', 'Illinois , United States']
SQL:

assistant: SELECT SUM("Round") FROM "Table" WHERE "Method" = 'Submission (choke)';