We present an equation of state and the composition of low-density supernova matter composed of light nuclei with mass number A \leq 13 .
We work within the quasiparticle gas model , which accounts for bound states with decay time scales larger than the relevant time scale of supernova and protoneutron star evolution .
The mean-field contribution is included in terms of Skyrme density functional .
Deuterons , tritons , and ^ { 3 } H ( e ) nuclei appear in matter in concentrations that are substantially higher than those of heavier nuclei .
We calculate the critical temperature of deuteron condensation in such matter , and demonstrate that the appearance of clusters substantially lowers the critical temperature .