user: Question: What party does William J. Jefferson?
Columns: ['District', 'Incumbent', 'Party', 'First elected', 'Results', 'Candidates']
Types: ['text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['Louisiana 1', 'Bob Livingston', 'Republican', 1977.0, 'Re-elected', 'Bob Livingston (R) (unopposed)']
SQL:

assistant: SELECT "Party" FROM "Table" WHERE "Incumbent" = 'William J. Jefferson';