Hiring someone with that much (or even half that much) experience shouldn't include a coding exercise. If it does, the results should contribute ~5%-10% weight to the final decision. Seniors'/leads' skills diverge from engineering over time. You shouldn't even be coding as a lead. You direct the coding of juniors. When I interview those upper levels, I talk more about design and how they work with other departments (ops, product, UI) to get things done; how they overcome people and process problems.
I know several leads who can write great code, but they can't lead a project to completion for the life of them. And if you discover that during the interview, you have to determine whether it was genuinely their lack of competence or because of poor management. Personally, I'd rather spend that hour allotted to coding digging more deeply into their non-coding skills.