The difference in maximum aperture doesn't mean as much as you might think. It is usually OK to hold the 35 at 1/60 and the 50mm lens requires at least 1/80 to avoid the effects of hand movement while holding the lens. Also, many people don't want to shoot the 50 at f1.4, since their copies are a little soft there. Mine is pretty good at f1.4, but indoors, I like larger f stops with the 50 - like f1.8 to increase depth of field. Even if you want to shoot the 50 at f1.4, the difference is not a full stop, because of the need for most people for higher shutte speeds with the 50.
Focal length does matter here. The 50 is now in a lens case, but often winds up on a second body, while the camera I often reach for has the 35 on it.
My answer to the original question is still that they are both very good in low light, but I use my 35f2 more.
Now, the 35f1.4 - that is a different issue entirely.