Why was lead carbonate formed?

prepare an electrolytic cell using 100mL of a 4% solution of KClO3 and 100mL of a 1% solution of Na2CO3 in a 250mL beaker. Then using two strips of lead as electrodes electrolyze at about 8 volts. After doing this, a precipitate was dissolved on one of the pieces of lead. but why was it formed on one and not the other one