user: Question: In how many districts was the Democratic incumbent elected in 1974? 
Columns: ['District', 'Incumbent', 'Party', 'Elected', 'Status', 'Opponent']
Types: ['text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['North Carolina2', 'Tim Valentine', 'Democratic', 1982.0, 'Re-elected', 'Tim Valentine (D) 74.7% Hal C. Sharpe (R) 25.3%']
SQL:

assistant: SELECT COUNT("District") FROM "Table" WHERE "Party" = 'Democratic' AND "Elected" = 1974.0;