NEW YORK (AP) — Sia will be the musical guest on “Saturday Night Live” on Nov. 7. And even she must realize she won’t be the reason so many people will tune in. The host that week: Donald Trump, the GOP presidential front-runner who has been a proven ratings winner whenever he shows up on the ol’ flat-screen. It’s Trump’s second time on the show; he did SNL back in 2004, before his presidential aspirations manifested themselves.