Hi,
Couldn't find a Levi Jonas born in Cornwall, but there are these two from Devon...
1871 (Transcribed as Jones)
Clam? Cottage, North Huish, Devon
Thomas Jonas, Head, W, 55, Tailor, Diptford
Alan Jonas, Son, 14, Scholar, Diptford
Noah Jonas, Son, 9, Scholar, Diptford
Levi Jonas, Gson, 6, Scholar, Diptford
RG10/2097 Pg14
Harbertonford, Harberton, Devon
William Bickford, Head, 32, Labourer, Harberton
Susanna Bickford, Wife, 26, Dittisham
Levi Jonas, Visitor, 23, Blacksmith, Diptford
Mary G Jonas, Visitor, 25, Harberton
& 3 Lodgers
RG10/2098 Pg6
1861
Jonas Cottage, Diptford
Thomas Jonas, Head, 45, Baker, Grocer & Road Contractor, Diptford
Mary Ann Jonas, Wife, 42, Diptford
Ezra? Jonas, Son, 20, Carpenter, Diptford
Leah Jonas, Daughter, 17, Seamstress, Diptford
Levi Jonas, Son, 13, Scholar, Diptford
Lucy Jonas, Daughter, 8, Scholar, Diptford
Alan Jonas, Son, 4, Scholar, Diptford
RG09/1420 Pg13
1851
Ezra Jonas Diptford Totnes, Devonshire Diptford, Devonshire, England Male 10
Leah Jonas Diptford Totnes, Devonshire Diptford, Devonshire, England Female 7
Levi Jonas Diptford Totnes, Devonshire Diptford, Devonshire, England Male 3
Mary A. Jonas Diptford Totnes, Devonshire Diptford, Devonshire, England Female 32
Thomas Jonas Diptford Totnes, Devonshire Diptford, Devonshire, England Male 33
Nicholas Parsons Diptford Totnes, Devonshire North Huish, Devonshire, England Male 55
If you want any further info from later census records, let me know!
Regards, Emma