user: Question: Name the least clubs involved for leagues being none for Semi finals
Columns: ['Round', 'Clubs remaining', 'Clubs involved', 'Winners from previous round', 'New entries this round', 'Leagues entering this round']
Types: ['text', 'real', 'real', 'text', 'text', 'text']
Sample row: ['Preliminary round', 129.0, 34.0, 'none', '34', 'Levels 4 and 5 in football league pyramid']
SQL:

assistant: SELECT MIN("Clubs involved") FROM "Table" WHERE "Leagues entering this round" = 'none' AND "Round" = 'Semi finals';