The English translation doesn't work. It either needs to be past tense: "That is the third time I supported her." or a present progressive: "That is the third time I am supporting her." Although "That" still is awkward, "This" would be better but wouldn't match the Vietnamese of "Đó" then.
Please be advised that there's a difference between main translations and unsupported (rejected) translations. In this case, both "support" and "have supported" are listed as primary answers.
Just so you know, Vietnamese language does not have perfect tense. It only have fourvery straightforward tenses: past, simple continuous and future.