Praise be to Allah.
There is no proof that the Prophet (peace and blessings of Allah be upon him) said any du`a during wudu whilst washing or wiping his limbs, etc.
Any such du`as that are known are bid’ah (innovation) and have no basis.
What is known from Islamic sources is that one should say “Bismillah ar-Rahman ar-Rahim ” at the beginning, and after finishing one should recite the Shahadatayn (testimony of faith) and say, “Allahumma ij’alni min al-tawwabin waj’alni min al-mutatahhirin (O Allah, make me one of those who repent and make me one of those who purify themselves).”
And Allah knows best.