user: Question: What is Votes (%), when First Broadcast is "13 March 1998"?
Columns: ['Episode', 'First broadcast', "Graeme's guest", "Jeremy's guest", 'Votes (%)']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['1x01', '27 February 1998', 'Maria McErlane', 'Tony Hawks', '75–25']
SQL:

assistant: SELECT "Votes (%)" FROM "Table" WHERE "First broadcast" = '13 March 1998';