Otra prueba:

import sqlite3

# leo DB
#dbfn = 'allseqs-AR.db'
dbfn = '../AS/allseqs-AS.db'
conn = sqlite3.connect(dbfn)
c = conn.cursor()
# CREATE TABLES
c.execute("SELECT ctgID,read from ctgs")
for row in c:
    ctg = row[0]
    lib = row[1].split('-')[0][-3:]
    #break

FIN de prueba.