diff --git a/circuits/select.circom b/circuits/select.circom
index 828159a..4e356bd 100644
--- a/circuits/select.circom
+++ b/circuits/select.circom
@@ -76,7 +76,7 @@ template SELECT(nColumns, nRows, nAND, nOR) {
         }
 
         for (j=0; j<nColumns; j++) {
-            assert(fields[j] >= 0 && fields[j] <= 1);
+            (field[j] - 1) * field[j] === 0;
             isCell[i][j] <== filterRow[i].out * fields[j];
             results[i][j] === table[i][j] * isCell[i][j];
         }