Looks like it's mostly Russia and China, with unconfirmed estimates for other countries. This is in violation of UN sanctions, so it's highly unlikely that you'd meet a N. Korean in countries that respect UN sanctions.

South Korea, on the other hand, numbers in the millions. So if you live outside of Russia and China, there are millions of S. Koreans vs probably a few thousand N. Koreans. It's not even close.

Plus about 50,000 have managed to defect over the past 30 years.

Yes, defectors exist, but they're so vanishingly few that it makes no sense to ask. Average defectors are something like 1-2k/year, and by comparison, about 16-17k S. Koreans immigrate to the US every year. So the chance that the person you're talking to is from N. Korea is incredibly small, not only do very few people actually escape N. Korea, they likely largely stay in S. Korea, where they speak the language.

"Korea" is the proper name for both countries, the "North" and "South" descriptor comes from other countries to disambiguate them. The official name for S. Korea is "Republic of Korea," and the official name for N. Korea is "Democratic People's Republic of Korea." So if you're wanting people to fully state the country they're from, you'd probably be more confused because both countries' official names include "Republic of Korea." But you'll likely never talk to someone from N. Korea, so the whole question is moot. If they say they're from "Korea," 99.9% of the time they'll be from South Korea, and if you live outside of S. Korea, it's probably like 99.999%.

Nobody will be confused if you tell them you’re American

Left Coast!