There's no benefit running in 64 bit if you only have 4 gigs total. You're way better off maxing out your ram and running
Logic in 64 bit. These days if I try to boot up a normal session in 32 bit Logic just quits as I'm way over 4 gigs
Even with "only" 4 GB RAM, Logic may be more stable in 64 bit Mode when RAM is running out. Worth experimenting with. If you experience a crash in 32 bit mode, try to reproduce this running in 64 bit mode. If you can't, there's your benefit.
But the real solution is very straightforward: Get more RAM