The $\mathsf{P}$-complete problems can be considered "inherently sequential". $\mathsf{P}$-completeness may be defined using either $\mathsf{NC}$ reductions or $\mathsf{L}$ reductions.
Since $\mathsf{L}\subseteq\mathsf{NL}\subseteq\mathsf{NC^2}\subseteq\mathsf{NC}\subseteq\mathsf{P}$, an $\mathsf{NC}$ reduction should be at least as powerful as an $\mathsf{L}$ reduction. What separations or equivalences are known between these two types of reductions?