user: Question: When was the incumbent in the Tennessee 4 district first elected? 
Columns: ['District', 'Incumbent', 'Party', 'First elected', 'Results', 'Candidates']
Types: ['text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['Tennessee 1', 'William L. Jenkins', 'Republican', 1996.0, 'Re-elected', 'William L. Jenkins (R) 69% Kay White (D) 31%']
SQL:

assistant: SELECT "First elected" FROM "Table" WHERE "District" = 'Tennessee 4';