Teaching one student who is very good and another who is bad was a learning experience.
Teaching a student who is very good and the other who is bad was a learning experience.
One side of the coordinating conjunction uses "one student", the other side only uses "another." The parallelism of this usage depends on whether the term "student" carries over from first clause of "and" to the second clause that begins with "another" making it "another student."
does it need to be "another/other student?"
Cite the rule for why or why not.