def select_stitched_contigs(cxn, ref_name, taxon_name, iteration=0):
    """Select stitched contigs for a reference taxon pair."""
    return cxn.execute(
        """SELECT *
             FROM stitched
            WHERE ref_name   = ?
              AND taxon_name = ?
              AND iteration  = ?
         ORDER BY position
        """,
        (ref_name, taxon_name, iteration))