ANSWER:
You can say any dua you want.
Abu Hurayrah said: the Messenger of Allah (peace and blessings of Allah be upon him) said: “When any one of you recites the Tashahhud [according to one report: when any one of you finishes the final Tashuhhud ], let him seek refuge with Allah from four things, let him say: ‘Allahumma inni ‘a’udhu bika min ‘adhabi Jahannam wa min ‘adhab al-qabri wa min fitnat il-mahya wa’l-mamat wa min sharri fitnat il-masih id-dajjal (O Allah, I seek refuge with You from the punishment of Hell and the punishment of the grave, and from the trials of life and death and from the worst of the turmoil of the Dajjal (antichrist)).’” Sahih Muslim, 588.