user: Question: How many rounds did Brett go for the Strikeforce: Shamrock vs. Diaz match?
Columns: ['Res.', 'Record', 'Opponent', 'Method', 'Event', 'Round', 'Time', 'Location']
Types: ['text', 'text', 'text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['Win', '13–5 (1)', 'Evgeny Erokhin', 'Decision (split)', 'FEFoMP: Mayor cup 2013', 3.0, '5:00', 'Yuzhno-Sakhalinsk , Russia']
SQL:

assistant: SELECT "Round" FROM "Table" WHERE "Event" = 'Strikeforce: Shamrock vs. Diaz';