user: Question: What was the 1st leg of the match that had an aggregate of 4-3?
Columns: ['Team 1', 'Agg.', 'Team 2', '1st leg', '2nd leg']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['Botafogo (RJ)', '3-1', 'Corinthians (SP)', '1-0', '3-1']
SQL:

assistant: SELECT "1st leg" FROM "Table" WHERE "Agg." = '4-3';