Which city is most likely to be at 13N latitude and 105 E longitude?

Latitude/longitude coordinates describe exact points, and don't involve probability.

Once you have a set of numbers, the point is defined. Whatever is there, is there,

and whatever isn't there, is definitely somewhere else.

That point is in northeast-central Cambodia, in a sparsely wooded area that's

about 5.5 km east of National Highway 64. The point is 34.1 km north-northeast

of the center of Kampong Thom, 161.7 km north of the Phnom Penh International

Airport, and the point itself is not in any city.