user: Question: To what district does Bill Hefner belong?
Columns: ['District', 'Incumbent', 'Party', 'First elected', 'Status', 'Opponent']
Types: ['text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['North Carolina1', 'Eva M. Clayton', 'Democratic', 1992.0, 'Re-elected', 'Eva M. Clayton (D) 61.1% Ted Tyler (R) 38.9%']
SQL:

assistant: SELECT "District" FROM "Table" WHERE "Incumbent" = 'Bill Hefner';