user: Question: Which polling institute showed a lead of 6%?
Columns: ['Date(s) Released', 'Polling institute', 'Nationalist', 'Labour', 'Democratic Alternative', 'Undecided/ No answer', 'Lead']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['7 January 2012', 'The Sunday Times', '25.2% (46.9%)¤', '29.5% (52.1%)¤', '1.0% (1.0%)¤', '44.3%', '4%']
SQL:

assistant: SELECT "Polling institute" FROM "Table" WHERE "Lead" = '6%';