It's not just heirs, but "heirs, successors, and assigns" (if that even makes a difference). A quick search of Ohio case law turned up Schafer v. Deszcz, 698 N.E.2d 60, 120 Ohio App.3d 410 (Ohio App. 6 Dist., 1997), which stated in part:
Originally Posted by seniorjudge
Additionally, the terms in Section D of the Declaration of Restrictions grants the right of first refusal to, inter alia, National Resort Lands, Inc. (the grantor) and all purchasers (the grantees) and their respective successors, heirs and assigns. Clearly, this language demonstrates that the right of first refusal is not personal to the grantee. Furthermore, the right is of an unlimited duration, and at the time it was created, the possibility existed that it might not be exercised until after the expiration of the period fixed by the rule against perpetuities, if ever. Therefore, the trial court did not err in determining that the right of first refusal in the Declaration of Restrictions was void.