CREATE TABLE table_19089486_1 (clubs_involved NUMBER, leagues_entering_this_round VARCHAR2, round VARCHAR2)

Name the least clubs involved for leagues being none for semi finals
SELECT MIN(clubs_involved) FROM table_19089486_1 WHERE leagues_entering_this_round = "none" AND round = "Semi finals"
SELECT MIN("clubs_involved") FROM "table_19089486_1" WHERE "Semi finals" = "round" AND "leagues_entering_this_round" = "none"