user: Question: What is the earliest first elected date of incumbent Howard McKeon?
Columns: ['District', 'Incumbent', 'Party', 'First elected', 'Results']
Types: ['text', 'text', 'text', 'real', 'text']
Sample row: ['California 1', 'Mike Thompson', 'Democratic', 1998.0, 'Re-elected']
SQL:

assistant: SELECT MIN("First elected") FROM "Table" WHERE "Incumbent" = 'Howard McKeon';