Who knows 13? I know 13. 13 are the attributes of God
12 are the Tribes of Israel
11 are the stars in Joseph’s dream
10 are the commandments
9 are the months before birth
8 are the days to the brit milah
7 are the days in a week till Shabbat
6 are the orders of the Mishnah
5 are the books of the Torah
4 are our matriarchs
3 are our forefathers
2 are the tablets of the commandments
1 is Our God who is in the heavens and on earth. 

haggadah Section: Nirtzah
Source: JQ International GLBT Haggadah