user: Question: What is the start date with Luke Jacobz hosting and Dannii Minogue as a winning mentor?
Columns: ['Series', 'Start', 'Finish', 'Winner', 'Runner-up', 'Third place', 'Winning mentor', 'Main host']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['One', '6 February 2005', '15 May 2005', 'Random', 'Russell Gooley', 'Vince Harder', 'Mark Holden', 'Daniel MacPherson']
SQL:

assistant: SELECT "Start" FROM "Table" WHERE "Main host" = 'Luke Jacobz' AND "Winning mentor" = 'Dannii Minogue';