hello~ sorry i am not sure which "答辩" do you mean? can you give some details?
if you mean "论文答辩/毕业答辩",that's "thesis defense",or "graduation reply"."答辩考试" "competitie examination".like these words above,in Chinese generally we can say "答辩". "答辩" also means "plea","defence".
hmm~ hope my answer could help you some~ ^^