user: Question: Who is the constituency when the runner-up was D. Venugopal? 
Columns: ['Constituency', 'Winner', 'Party', 'Margin', 'Runner-up a', 'Party a']
Types: ['text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['1. Chennai North', 'D. Pandian', 'Indian National Congress', 118518.0, 'Aladi Aruna', 'DMK']
SQL:

assistant: SELECT "Constituency" FROM "Table" WHERE "Runner-up a" = 'D. Venugopal';