user: Question: When did the term began when the date of election is N/A?
Columns: ['Office', 'Type', 'Location', 'Elected', 'Term began', 'Term ended']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Mayor', 'Executive', 'San Francisco', 'N/A', 'December 4, 1978', 'January 8, 1980']
SQL:

assistant: SELECT "Term began" FROM "Table" WHERE "Elected" = 'N/A';