CREATE TABLE table_5597 ("Date Released" CLOB, "Institute" CLOB, "Socialist" CLOB, "Social Democratic" CLOB, "Green-Communist" CLOB, "Left Bloc" CLOB, "People's Party" CLOB, "Lead" CLOB)

Name the lead for institute of election results and social democratic of 31.7% 8 seats
SELECT "Lead" FROM table_5597 WHERE "Institute" = 'election results' AND "Social Democratic" = '31.7% 8 seats'
SELECT "Lead" FROM "table_5597" WHERE "Institute" = 'election results' AND "Social Democratic" = '31.7% 8 seats'