Is there a jailbreak available for iOS 6.1.3?
Yes. An unearthed jailbreak. Look up jailbreak 6.1.3 on YouTube and you should find a video of mine to help :)
i'm not sure but evasi0n don't...
I don't recommend jail breaking. It makes your iPod run slower. And the wrong jailbreak could wreck your iPod.
You also loose warranty