Well it depends on what type of loss LSU has. If LSU's 1 loss is in the SEC Champ game in a close game against Georgia then that means they beat Bama. I could see them getting in ahead of Iowa. If Georgia blew them out in the SEC Champ game then maybe undefeated Iowa gets in.
If LSU's only loss is to bama in a close game they might take LSU unless the SEC east champs only loss is in the SEC Champ game, say a 12-1 Georgia team.
Personally if Iowa is 13-0 with this schedule and beating probably OSU in the Big title game there really is almost 100% chance they are in the cfp.