Retrieving corresponding column values based on row label

Question

So i have a set of data in excel:

StudID          Score            Participation

100              54                  0.43
432              70                  0.65
321              98                  0.96
100              65                  0.55

and I read it into R:

stud_stat <- read.csv("student.csv")

What I'm trying to do now is to only retrieve the score and participation values based on a specific ID. For example, if the ID is 100 i would want:

StudID          Score            Participation

 100             54                  0.43
 100             65                  0.55

I did something like:

find <- stud_stat[which(stud_stat$StudID == "100")]

and I'm getting an error mentioning about undefined columns selected.