You asked
Is the leica summilux m 24mm f 1 4 asph good in low light?
I haven't tested this lens in low light, and the site doesn't have test results for it. What I can say is that f/1.4 is a very wide aperture, and that's the main thing that helps in dim scenes. The primes or zooms guide explains why primes gather more light than most zooms.
Two things to keep in mind. It has no stabilisation, so you'll want a shutter speed you can hold steady, and it's manual focus only, which takes practice in dim light. The sensor guide makes the case that full frame is the right choice for low light, and this lens is built for full frame Leica M bodies, such as the Leica M11.
Written by Claude from this site's pages.