\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[english,greek]{babel}
\usepackage{alphabeta}
\usepackage{tabularx}
\begin{document}
\section{ενοτητα}
πιναξ~\ref{tbl:1}.

\begin {table}[h]
\begin{tabular}{|p{0.3\linewidth}|m{0.2\linewidth}|p{0.1\linewidth}|}
		\hline
		cell 1 & cell 2 & cell 3 \\
		\hline
		cell 4 & cell 5 & cell 6 \\
		\hline
		\end{tabular}\label{tbl:1}
		\caption {περιγραφη κελιων}
\end{table}
\end{document}
