user: Question: Name the lead for institute of Election Results and social democratic of 31.7% 8 seats
Columns: ['Date Released', 'Institute', 'Socialist', 'Social Democratic', 'Green-Communist', 'Left Bloc', "People's Party", 'Lead']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['7 June 2009', 'Election Results', '26.5% 7 seats', '31.7% 8 seats', '10.6% 2 seats', '10.7% 3 seats', '8.4% 2 seats', '5.2%']
SQL:

assistant: SELECT "Lead" FROM "Table" WHERE "Institute" = 'Election Results' AND "Social Democratic" = '31.7% 8 seats';