Ohio's 12th District sits in suburban Columbus and juts into part of the city. Tiberi has represented the area since 2001. He announced his resignation this year and plans to lead the Ohio Business Roundtable.
Tiberi won more than 60 percent of the vote in each of his last three re-election bids.
The GOP has a more than two-to-one affiliation advantage in the district, according to Sabato's Crystal Ball. Still, more than half of the district's registered voters are unaffiliated.
Ohio's 12th District, like Pennsylvania's 18th, is better educated, wealthier and has a lower jobless rate than the median congressional district, according to U.S. Census data. A higher proportion of voters in Ohio's 12th District have college or post-graduate degrees than voters in Pennsylvania's 18th District do, and the median household income there is higher.
Crowded fields on both the Republican and Democratic sides are vying for the seat. Republican candidates include state Sens. Troy Balderson and Kevin Bacon. Democrats running include Franklin County Recorder Danny O'Connor and former Franklin County Sheriff Zach Scott.
If a Democrat has a shot of winning the district, the candidate will likely need to win over highly educated independents and Republicans in Columbus' outskirts who disapprove of Trump. Having to go through a primary process could make that more difficult for a Democrat in Ohio than it was for Lamb, said Mark Weaver, a Republican strategist at the Columbus-based Communications Counsel.
To win a primary election, candidates often have to go closer to their party's extremes. It can make them less appealing to general election voters.
Republicans have argued Lamb had an easier path than other candidates will this year because he did not face a primary election. It allowed him to take moderate stances that would not have held up had he gone through a primary, they contend.
"Most Democratic primaries won't produce a former Marine, former prosecutor, good-looking white guy who loves to shoot AR-15s and who says he's personally pro-life and wants to toss out Nancy Pelosi," said Weaver, who is working as a consultant for the GOP candidate Bacon and has worked with Balderson in the past.
Of course, the primary election concerns go both ways. Weaver says the risk for Republicans in the district is nominating someone whose views skew too far to the right "who cannot win a general election."
That may prove particularly important in Ohio's 12th District, where voters are more educated than the median congressional district. Highly educated voters generally tend to have more socially liberal views and take more time to research and understand the candidates.
Voters will have a clearer view of the candidates after May 8, when the special primary will be held. The special election will take place on August 7.