I mean this scenario is possible but in probability, what odds would you give a chance for pregnancy if sperm was on thigh for 2 min then brought up to the labia by a thong. can sperm swim from labia to the vaginal hole?

Very unlikely,: Very low chance of pregnancy. Recommend seeing your doctor for a consistent, effective contraceptive treatment plan.

In real life...: In real life, that does not happen. There generally is not enough semen to go up or down a thigh, over the vulva, an into the vagina. Ejaculation usually has to happen into the vagina in order to create a new baby. That being said, life can surprise you sometimes. So, couples having sex should always be ready for that rare surprise baby.