Yes, you can get pregnant from that kind of close encounter. Part way is just as risky as all the way. Even if he didn't put his penis inside you at all, if there was any contact with your genital area, the sperm could have been deposited and it can travel through moist tissue and enter your vagina.

If he ejaculated you would be most at risk, but even if he didn't, a few drops of semen could still leak out. All it takes is one single sperm to find your egg and make you pregnant. So always insist that your partner wear a condom if you have any sexual contact.