user: ### NOW ANSWER:
Question: Who conducted the poll with sample size of 2000 that shows 18% undecided?
Columns: ['Date of opinion poll', 'Conductor', 'Sample size', 'For', 'Against', 'Undecided']
Types: ['text', 'text', 'real', 'text', 'text', 'text']
Sample row: ['27 September 2009', 'Sunday Independent/Quantum Research', 1000.0, '68%', '17%', '15%']
SQL:

assistant: SELECT "Conductor" FROM "Table" WHERE "Undecided" = '18%' AND "Sample size" = 2000.0;