Yes! Because it just takes a single sperm to fertilize an egg, and any one of these fast swimmers entering the vagina can make its way to meet one. Even when your partner pulls out "correctly", which means he pulls out his penis before ejaculation, he can release some sperm before he comes. And that of course can get you pregnant. Also, sperm can survive for up to 6 hours outside the body, for example on hands. Once the sperm have been transferred into the woman, through foreplay or other means, it is possible for them to reach an egg.
And to bring the point home: pulling out correctly is no easy feat; neither is it fail-safe. Even "withdrawal kings" – guys who always pull out in time, fall prey to that 20% pregnancy rate (which is very high compared to other methods of contraception).