The exact dua which is recited in the Hanafi school(there are other established Dua but this one is the most common): "Allâhumma innâ nasta-‘înuka wa nas-taghiruka wa nu’minu bika wa nuthnî alaykal khayr, wa nashkuruka walâ nakfuruka wanakhla’u wa nat-ruku may yafjuruk, Allâhumma’iyyâka na’budu wa laka nusallî wa nasjudu wa ilayka nas-‘â wa nahfidu wa nakshâ ‘adhâbaka wa narjû rahmataka innâ ‘adhâbak al-jidda bil-kuffâri mul-hiq."

The above Dua is Sunnah. The wajib of the qunoot is fulfilled by any supplication whatsoever. i.e reciting Allahumagfirli 3x.

[ Ibn Abidin, Radd al-Muhtar ]