Size of pan more info in details

A 9x13 has a surface area of 117 square inches (9*13=117). A 9-inch round pan has a surface area of 63.6 square inches (3.14*4.5*4.5), so two would have a surface area of ~127 square inches. So it should be fine, but it will be a little thinner than the cake layers would be, so I would start checking it a few minutes before the recipe says. I wouldn't recommend baking it in a ceramic 9x13, though, as ceramic's ability to retain heat and insulate means you may end up with overbaked edges and an underbaked center.