NOTE:  the elder daughter and her marriage to Christian KAHLE are tentative; the evidence is entirely circumstantial.

1.  Anon.  1966.  Marriage Index:  Ohio, 1789-1850.  Liahona Research, Orem, UT (Broderbund CD-400):  not found, as expected.

2.  Family Quest Archives:  Ohio Federal Census 1850: Hancock and Hardin Counties.  Heritage Quest CD M432-692:  Cessna Twp., Dist. No. 49, Hardin Co., OH, p. 209A, 1351/1351, enumerated 9 Aug 1850 (extracted by Diana Gale Matthiesen):

Jacob Diddlebaugh	47	M	Farmer	2000	Germany
Rosana Diddlebaugh	50	F			Do
Francis Diddlebaugh	17	M			Do
Jennet? Diddlebaugh	14	F			Do
Joseph Kahle	2	M			O

Living next door to Christian KAHLE, a lone male, age 37, born in Germany.  There's a strong probability that Christian was married to one of Jacob & Rosanna's daughters, who has died, and that Joseph KAHLE is Jacob & Rosanna's grandson.

3.  1860 Census Images (online at Ancestry.com; Image #5 of 13):  Dunkirk P.O., Cessna Twp., Hardin Co., OH, p. 402B, PN 84, 563/563, enumerated 11 Jul 1860 (extracted by Diana Gale Matthiesen):

Jacob Didlebough	57	m		Farmer	4500	1000	Wortemburg
Rose Ann	62	f					"
Joseph	12	m					O

Joseph is Joseph KAHLE, whom I suspect is their orphaned grandson.  Living next door to Jacob's son, Francis, and his family.

4a.  Family Quest Archives:  Ohio 1870 Census Index.  Heritage Quest ACD-0014:  Jacob was not indexed.

Surname	Given name	Age	Sex	Race	Birth Place	County	Locality	Roll	Pg
Diddlebaugh	Janette	12	F	W	OH	Hardin	Cessna Twp	1219	344

Jacob was not indexed.

4b.  1870 Census Images (online at Ancestry.com; Image #4 of 19):  Kenton P.O., Cessna Twp., Hardin Co., OH, p. 344B, PN 4, enumerated 3 Jun 1870 (extracted by Diana Gale Matthiesen):

1

2

3

4

5

6

7

8

9

10

11

12

15

19

29

26

Eccarius Valentine

57

m

W

Farmer

5850

1400

Saxony

/

/

/

________ Janette

32

f

W

Keeps house

Pennsylvania

/

/

________ Jacob G

11

m

W

working farm

Ohio

/

/

________ Margaret R

9

f

W

at home

"

/

/

Stahl Francis M

26

m

W

working farm

"

/

Diddlebaugh Janette

12

f

W

at home

"

/

/

___________ Jacob

67

m

W

(Infirm)

2000

Wurtemburgh

/

/

/

Although the age is slightly off and the birthplace inconsistent, I'd still wager that Mrs. Janette ECCARIUS is Jacob's daughter.  Janette DIDDLEBAUGH is Jacob's granddaughter, orphan of his deceased son, Francis.  Jacob's probable grandson, Joseph KAHLE, is twelve households away (on p. 344A, 17/15).