When you are sober it's fine to breastfeed for future reference. Once the alcohol is out of your bloodstream it's also out of your milk then its save to nurse or pump. If it's one drink they say wait 1-2 hours
You don't need to pump and dump! I researched it. You can breastfeed when you no longer feel the effects of alcohol. You should look it up! No reason to waste milk if you don't have to.