Table schema:
CREATE TABLE table_18143210_2 (number_of_seasons_in_top_division INTEGER, first_season_in_top_division VARCHAR)

Question: How many 'number of seasons in top division' were played if the 'first season in top division' games is in 1990-91?
SQL: SELECT MAX(number_of_seasons_in_top_division) FROM table_18143210_2 WHERE first_season_in_top_division = "1990-91"