It strikes me as odd that in today's day and age, people still have questions as too what it takes to get pregnant. I hope you do not take offense to that statement but honestly, if you do not know that the only way to get pregnant is to have seamen inside your vagina, then maybe you are not mature and or educated enough on the subject to actually be having sex in the first place. Honestly, how could you think you can get pregnant by having seamen on your leg? Unless he came on your cookie as opposed to inside it, then there could be a chance, however slight of a chance it is.
Finally to answer your question...
You can not get pregnant from having seamen on your leg.
Nygut is right.Unless he came on your vagina,there is no chance that you're pregnant.If he came on your leg,not on your vagina,you are okay.If there was no contact with your vagina,fine.Even without penetration,if there was semen on your vagina,there is a very slight chance of pregnancy.On the leg,no chance.Please get some form of birth control if you are going to have sexual contact,even if you are not having full penetration.Better to be safe than sorry.If you and your boyfriend are taking things this far,it's very easy to get carried away and have sex.Have birth control before you need it!!!Good luck to you.Patty