Table schema:
CREATE TABLE table_name_6 (seats INTEGER, general_election VARCHAR, share_of_votes VARCHAR, share_of_seats VARCHAR)

Question: Which Seatshave a Share of votes of 18%, and a Share of seats of 3%, and a General election smaller than 1992?
SQL: SELECT MIN(seats) FROM table_name_6 WHERE share_of_votes = "18%" AND share_of_seats = "3%" AND general_election < 1992