\begin{table}
	\centering%
	\begin{tabular}{lll}
	\toprule
	First 	& Second 		& Third \\
	\midrule
	1 	& 			& \multirow{2}{80pt}{AB} \\
	2 	& 			& 	\\
	3 	& \multirow{-3}{*}{123} & C     \\
	\bottomrule
	\end{tabular}
\end{table}

The multirow command is defined as follows:

\multirow{nrows}{width}{content}