user: Question: Which district has a Democratic incumbent that was first elected before 1996?
Columns: ['District', 'Incumbent', 'Party', 'First elected', 'Results']
Types: ['text', 'text', 'text', 'real', 'text']
Sample row: ['Oregon 1', 'David Wu', 'Democratic', 1998.0, 'Re-elected']
SQL:

assistant: SELECT "District" FROM "Table" WHERE "Party" = 'Democratic' AND "First elected" < 1996.0;