CREATE TABLE table_50463 ("Series" TEXT, "Start" TEXT, "Finish" TEXT, "Winner" TEXT, "Runner-up" TEXT, "Third place" TEXT, "Winning mentor" TEXT, "Main host" TEXT)

What is the start date with Luke Jacobz hosting and Dannii Minogue as a winning mentor?
SELECT "Start" FROM table_50463 WHERE "Main host" = 'luke jacobz' AND "Winning mentor" = 'dannii minogue'
SELECT "Start" FROM "table_50463" WHERE "Main host" = 'luke jacobz' AND "Winning mentor" = 'dannii minogue'