OID value: 1.1
RFC 2251, Section 4.5.1: 'If the client does not want any attributes returned, it can specify a list containing only the attribute with OID "1.1". This OID was chosen arbitrarily and does not correspond to any attribute in use.' The OID arc is also commonly used for examples.
URL for further info: http://www.rfc-editor.org/rfc/rfc2251.txt
See also the OID Repository website reference for 1.1