David took. No discrepancy here, for Joab had summoned David for the purpose (2 Samuel 12:27).
Related Commentaries of 1 Chronicles 20:2
1 Chronicles 20:2
2 And David took the crown of their king from off his head, and found it to weighb a talent of gold, and there were precious stones in it; and it was set upon David's head: and he brought also exceeding much spoil out of the city.