user: Question: What opponent uses the method of Decision and a 5-3 record?
Columns: ['Res.', 'Record', 'Opponent', 'Method', 'Event', 'Round', 'Time']
Types: ['text', 'text', 'text', 'text', 'text', 'real', 'text']
Sample row: ['Win', '12-5', 'Dave Keeley', 'Submission (guillotine choke)', 'RFC - Recife Fighting Championship 5', 1.0, '2:27']
SQL:

assistant: SELECT "Opponent" FROM "Table" WHERE "Method" = 'Decision' AND "Record" = '5-3';