avoid duplicate columns when node_aggregate_col is the same as node_id

python/cuxfilter/charts/core/non_aggregate/core_graph.py

@@ -50,7 +50,7 @@ def edge_columns(self):
 
     @property
     def node_columns(self):
-        if self.node_aggregate_col:
+        if self.node_aggregate_col != self.node_id:
             return [
                 self.node_id,
                 self.node_x,