CREATE TABLE table_29566686_1 (clubs_involved VARCHAR, leagues_entering_at_this_round VARCHAR)

How many different values of clubs involved were there when the league entering at this round was allsvenskan?
SELECT COUNT(clubs_involved) FROM table_29566686_1 WHERE leagues_entering_at_this_round = "Allsvenskan"
SELECT COUNT("clubs_involved") FROM "table_29566686_1" WHERE "Allsvenskan" = "leagues_entering_at_this_round"