اللهُمَّ إِنِّي أَسْأَلُكَ الْفِرْدَوْسَ.
Translation 
O Allah grant me Al-Firdaws!
Note: The prophet (may the peace and blessings of Allah be upon him) said: "If you were to ask Allah (i.e. for Paradise), then ask Him for Al-Firdaws, for it lays in the middle of Paradise, and it is the highest place in Paradise, and from thence flows the rivers of Paradise."
Transliteration
al-laa-hum-ma in-nee as’alukal fir-daws
Sources:
Bukhari No# 2790;
