Forget Iowa 1 and 3 as long as Hollywood and SJWs remain the face of the Democratic Party.
Despite the fact Obama EASILY won IA-01 and narrowly won IA-03? The third district will always be slightly challenging since David Young, while a complete bore, has Grassley connections, so he'll probably be safe for as long as he's there.
Don't let the 2016 results fool you; IA-01 is quite Democratic. Iowans HATED Clinton (even Democratic voters, who all, for some reason, voted for Gary Johnson instead of her) which explains why she did poorly there, especially compared to Obama. The House races fumbled in 2014 because Pat Murphy never had a competitive race before and assumed the seat would go blue (keep in mind this was a very narrow loss) and Vernon suffered the same fate in 2016 - everybody assumed she'd win because of the district's partisan lean and didn't even bother really competing here until it was too late.