usepackage[authoryear,sort,round]{natbib}
bibliographystyle{apa}

%ltxtable configuration
newcolumntype{L}{>{RaggedRightarraybackslash}X} % flush-left, while allowing hyphenation
newcolumntype{C}{>{Centeringarraybackslash}X} % centered, while allowing hyphenation
newcolumntype{P}[1]{>{RaggedRightarraybackslash}p{#1}}

usepackage{letltxmacro}

LetLtxMacro{originalcite}{cite}
deftablecite#1#{%
  defpretablecite{#1}%
  tableciteaux}
deftableciteaux#1{%
  textsuperscript{expandafteroriginalcitepretablecite{#1}}%
}
AtBeginEnvironment{table}{letcitetablecite}