13 And after he became the father of Shelah, Arphaxad lived 403 years and had other sons and daughters.a

Read Genesis 11:13 Using Other Translations

And Arphaxad lived after he begat Salah four hundred and three years, and begat sons and daughters.
And Arpachshad lived after he fathered Shelah 403 years and had other sons and daughters.
After the birth of Shelah, Arphaxad lived another 403 years and had other sons and daughters.