Duane - L. philadelphicum will be hardy in your neck of the woods. I would leave them in the pot and keep it outside with some protection over the winter (your oak tree will probably be sufficient), but you don't want the pot to freeze solid or get totally wet either. I can't really tell the dimension of the pot - 6" diameter and 9" tall perhaps? - but what to do with the seedlings is a decision to be made, as there are quite a few of them. You could leave them in the pot until next winter (2024), when the seedling bulbs will have grown some but they may be quite congested in there by that time, or you could take a chance and transplant them this winter after they have died-back. Don't transplant them earlier before their first true leaf has emerged as you will likely have a lot of losses. The other option would be to carefully take the soil and little bulbs out of the pot and put the whole thing in the ground this Fall without too much disturbance to the bulbs and roots and then try to separate them next Fall. Both options will probably work, but others on this Forum here might have some preference as how best to go.
Hope this helps, Steve
