Base catalyzed aldol condensation occurs with 

Acetaldehyde $\left({\mathrm{CH}}_3\mathrm{CHO}\right)$ shows aldol condensation, as it contains $\alpha -$hydrogen atoms.

A clear, easily flammable liquid, acetaldehyde. The strong, fruity scent of acetaldehyde makes it potentially difficult to breathe in high concentrations. Both plants and animals naturally create acetaldehyde, also known as ethanal.