The distributions of quarks in the pion and nucleon are extracted from measurements of the reaction ${\ensuremath{\pi}}^{\ensuremath{-}}N\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}X$ at 253 GeV/c in a naive Drell-Yan analysis, as well as QCD-corrected analyses at leading-log and next-to-leading-log order. As ${x}_{\ensuremath{\pi}}\ensuremath{\rightarrow}1$ the pion structure function shows a term that varies as $\frac{1}{{m}_{\ensuremath{\mu}\ensuremath{\mu}}^{4}}$, which we interpret as a higher-twist effect. Additionally, the angular distribution of the ${\ensuremath{\mu}}^{+}$ in the muon-pair rest frame tends towards ${sin}^{2}\ensuremath{\theta}$ as ${x}_{\ensuremath{\pi}}\ensuremath{\rightarrow}1$ and as ${m}_{\ensuremath{\mu}\ensuremath{\mu}}\ensuremath{\rightarrow}0$ in a manner consistent with higher-twist effects. When the strongly mass-dependent higher-twist effects are included as part of the pion structure function, the nucleon structure function agrees well with leading-twist results from deeply inelastic lepton-hadron scattering. A significant advance of the present work is the extension of the analysis to low masses by the subtraction of the $\frac{J}{\ensuremath{\psi}}$ and ${\ensuremath{\psi}}^{\ensuremath{'}}$ resonances from the continuum. Our analysis covers the kinematic range $0.4<{x}_{\ensuremath{\pi}}<1.0$ and $0.02<{x}_{N}<0.33$ with $3.0<{m}_{\ensuremath{\mu}\ensuremath{\mu}}<8.55$ GeV/${\mathit{c}}^{2}$. Cross sections for ${\ensuremath{\psi}}^{\ensuremath{'}}$ production are presented in an appendix.