'A'isha reported that the Messenger of Allah (ﷺ) used to pray thirteen rak'ahs during the night including the two rak'ahs (Sunan) of the dawn prayer.
Sahih Muslim Book 6, Hadith 151
← Previous Hadith This hadith has been narrated by Hisham with the same chain of transmitters.

Sahih Muslim Book 6, Hadith 150 Next Hadith → The Messenger of Allah (ﷺ) did not observe either in Ramadan or in other months more than eleven rak'ahs (of the night prayer). He (in the first instance) observed four rak'ahs. Ask not about their excellence and their length (i. e. these were matchless in perfection and length). He again observed four rak'ahs, and ask not about their excellence and their length. He would then observe three rak'ahs (of the Witr prayer). 'A'isha again said: I said: Messenger of Allah, do you sleep before observing the Witr prayer? He said: O 'A'isha, my eyes sleep but my heart does not sleep.

Sahih Muslim Book 6, Hadith 152