20 Amram married his father’s sister Jochebed, who bore him Aaron and Moses. Amram lived 137 years.

Read Exodus 6:20 Using Other Translations

And Amram took him Jochebed his father's sister to wife; and she bare him Aaron and Moses: and the years of the life of Amram were an hundred and thirty and seven years.
Amram took as his wife Jochebed his father's sister, and she bore him Aaron and Moses, the years of the life of Amram being 137 years.
Amram married his father’s sister Jochebed, and she gave birth to his sons, Aaron and Moses. (Amram lived to be 137 years old.)