conversion:Repeat_previous_if_empty_column

PREFIX conversion: <http://purl.org/twc/vocab/conversion/>
SELECT distinct ?dataset
WHERE {
  GRAPH <http://logd.tw.rpi.edu/vocab/Dataset>  {
    ?dataset a void:Dataset;
      conversion:conversion_process [
        conversion:enhance [
           a conversion:Repeat_previous_if_empty_column;
        ];
      ]
    .
  }
}