Dua for Second Ashra (2nd 10 days of Ramadan)
اَسْتَغْفِرُ اللہَ رَبِّی مِنْ کُلِّ زَنْبٍ وَّ اَتُوْبُ اِلَیْہِ
Astagfirullaha rab-bi min kulli zambiyon wa-atoobuilaiyh
I seek forgiveness from Allah for all my sins and turn to Him.
NOTE: There is no reference in Hadith for this Dua.