A March 13 special Congressional election in ruby-red western Pennsylvania has Republicans sweating — and Democrats smelling blood.

Democrats are spending $236,000 on TV ads for their candidate, Marine Corps veteran Conor Lamb, Politico reported.

The GOP has already made a million-dollar ad buy for Republican contender Rick Saccone, and right-leaning political PACs are shelling out even more.

President Trump won the district with 58 percent, but his approval rating there has sunk to 49 percent.